Multi-stage blowout preventer and method of using same

ABSTRACT

A blowout preventer includes a housing, a ram block carrier which moves within the housing, and one or more ram blocks configured to be placed within the ram block carrier. The ram block carrier may include an opening, an upper shelf within the opening configured to hold an upper ram block, and a lower shelf within the opening configured to hold a lower ram block. The housing may include a central bore, cavities on both sides of the bore, and openings which allow ram blocks to access a pipe within the bore.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A COMPACT DISK APPENDIX

Not applicable.

BACKGROUND

1. Field

The following description relates to blowout preventers used in the oil and gas industry during well drilling. For example, a ram-type blowout preventer is used to prevent escape of well bore pressure into the outside environment in the event of an unexpected pressure due to the influx of formation fluid or in other uncontrolled situations.

2. Description of Related Art

Well control is an important aspect of oil and gas exploration. Typically, when drilling a well, safety devices must be put in place to prevent damage to equipment and, most importantly, to personnel resulting from unexpected events associated with drilling operations. Because of safety conditions and risks of blowouts, devices known as blowout preventers (BOPS) are installed above the wellhead at the surface or on the sea floor in deep water situations to effectively seal a wellbore until measures can be taken to control the kick.

Blowout preventers are specialized high-pressure valves typically installed in stacks and used to seal and control downhole pressure and monitor oil and gas wells to ultimately prevent the uncontrolled flow of liquids and gases during well drilling operations. Additionally, blowout preventers are typically used to prevent tubing, tools and drilling fluid from being blown out of the wellbore when a blowout threatens. Blowout preventers come in a variety of styles, sizes and pressure ratings and several units serving various functions are typically combined to compose a blowout preventer stack. Blowout preventers may perform any of a variety of functions such as confining well fluid to the wellbore, providing means to add fluid to the wellbore, allowing controlled volumes of fluid to be withdrawn from the wellbore, regulating and monitoring wellbore pressure, centering and hanging off the drill string in the wellbore, shutting in the well, preventing the flow of formation fluid, and sealing the well.

Blowout preventers are critical to the safety of crew, rig and environment, and to the monitoring and maintenance of well integrity. Thus, blowout preventers are intended to be fail-safe devices. As recommend by authorities and required by various regulations, blowout preventers must be regularly tested, inspected, and refurbished. Blowout preventers typically include one set of corresponding ram blocks, and when the ram blocks need to be replaced or refurbished, companies are required by law to retest the entire blowout preventer stack. This may take long periods of time and may incur great expenses. A number of blowout preventers, including different types of ram blocks, are typically needed on the blowout preventer stack in order to serve a variety of different functions.

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

According to an example, a ram block carrier includes an opening, an upper shelf within the opening configured to hold an upper ram block, and a lower shelf within the opening configured to hold a lower ram block.

In another example, a housing of a blowout preventer includes a bore, a first cavity on a side of the bore, a second cavity on another side of the bore, and inside walls, adjacent to the first and second cavities, each comprising an opening which allows a ram block to access the bore.

In another example, a blowout preventer includes a housing, a ram block carrier configured to move within the housing, and one or more ram blocks configured to be placed within the ram block carrier.

In another example, a method of operating a blowout preventer includes moving a ram block carrier within the blowout preventer, and moving a ram block of the ram block carrier towards a pipe going through a bore of the blowout preventer.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the appended drawings. For the purpose of illustration, certain examples of the present description are shown in the drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of system, apparatuses, and methods consistent with the present description and, together with the description, serve to explain advantages and principles consistent with the invention.

FIG. 1 is a diagram illustrating a perspective view of an example of a blowout preventer.

FIG. 2 is a diagram illustrating a perspective view of an example of a blowout preventer in an open-door configuration.

FIG. 3 is a diagram illustrating a perspective view of an example of a housing of a blowout preventer.

FIG. 4 is a diagram illustrating a perspective view of an example of a ram block carrier of a blowout preventer.

FIGS. 5A and 5B are diagrams illustrating front and top cross-sectional views of an example of a blowout preventer including a hydraulic actuator and mechanical override mechanism for movement of the ram blocks.

FIG. 5C is a diagram illustrating an example of a ram block including a T-slot for connection to an actuating rod.

FIGS. 6A and 6B are diagrams illustrating side cross-sectional views of an example of a blowout preventer including a hydraulic actuator for movement of the ram block carrier into an upper and lower positions.

FIGS. 6C and 6D are diagrams illustrating an example of a blowout preventer including a mechanical override for movement of the ram block carrier into an upper and lower position.

FIGS. 7A and 7B are diagrams illustrating an example of a blowout preventer having a ram block carrier in a lower position and upper ram blocks in a retracted position and an engaged position.

FIGS. 8A and 8B are diagrams illustrating an example of a blowout preventer having a ram block carrier in an upper position and lower ram blocks in a retracted position and an engaged position.

FIG. 9 is a diagram illustrating a perspective view of another example of a blowout preventer including a circular rear door.

FIG. 10 is a diagram illustrating a perspective view of another example of a blowout preventer including circular ram doors.

FIG. 11 is a diagram illustrating a top cross-sectional view of another example of a blowout preventer including a hydraulic actuator and mechanical actuating mechanism for movement of the ram block carrier.

FIG. 12 is a diagram illustrating a side cross-sectional view of another example of a blowout preventer including a hydraulic actuator and mechanical actuating mechanism for movement of the ram block carrier.

Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness.

In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. For example, the use of a singular term, such as, “a” is not intended as limiting of the number of items. Also the use of relational terms, such as but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” are used in the description for clarity and are not intended to limit the scope of the invention or the appended claims. Further, it should be understood that any one of the features can be used separately or in combination with other features. Other systems, methods, features, and advantages of the invention will be or become apparent to one with skill in the art upon examination of the detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.

FIG. 1 is a diagram illustrating an example of a blowout preventer 100, and FIG. 2 is a diagram illustrating an example of a blowout preventer 100 in an open-door configuration.

Referring to FIGS. 1 and 2, a blowout preventer 100 includes a housing 110, a bore 120 going through a center of the housing 110, a rear door 130, ram doors 140 on two sides of the housing 110, hydraulic actuators 170 attached to the sides of the blowout preventer 100, and mechanical override stems 190 on the ends of the hydraulic actuators 170. As shown in FIG. 2, the housing 100 includes two cavities 124 for receiving ram block carriers 160.

The housing 110 includes a rear door 130 which is shown in a closed position in FIG. 1. In this example, the rear door 130 is attached to the housing 110 using fasteners 132 which bolt the rear door 130 to the housing 110 in a number of positions around the rear door 130. For example, the rear door 130 may be bolted to the housing 110 using six fasteners 132 but may be attached to the housing 110 using a variety of fasteners 132 in a variety of positions. The rear door 130 is in a closed configuration while the blowout preventer 100 is in use, but may be opened by removing the fasteners 132 and opening the rear door 130. The rear door 130 may be attached to the housing 110 by a door hinge or without a door hinge.

The housing 110 includes ram doors 140 which may be opened for inspecting, replacing, or removing components within the blowout preventer 100 such as ram block carriers, ram blocks, or other components. In this example, two ram doors 140 are attached to the body of the housing 110 using fasteners (not shown) similar to the fasteners 132 used for bolting the rear door 130. The ram doors 140 may include a number of holes 144 arranged around the doors 140 and configured to receive fasteners which are to be bolted to holes 112 formed within the housing 110. The ram doors 140 may be attached to the housing 110 using door hinges 142 so that the doors may be swung to an open position about the hinges 142 once the fasteners are removed.

FIG. 3 is a diagram illustrating an example of the housing 110 and displaying an interior of the housing 110.

Referring to FIG. 3, the housing 110 includes cavities 124 for receiving ram block carriers 160. The interior walls of the housing 110, which are formed around the cavities 124, include openings for allowing ram blocks 182, 184, discussed below, installed within the ram block carriers 160 to be pushed towards and close in on the bore 120. Outer walls of the housing 110, also adjacent to the cavities 124, include grooves 114, 115 for interacting with the ram block carriers 160, side openings 116 for receiving components of the hydraulic actuators 170. The bottom walls formed adjacent to the cavities 124 include drain holes 119 for draining residue fluids which enter the housing 110 during the drilling process. The interactions between the grooves 114, 115 of the housing 110 and the ram block carriers 160 will be explained in more detail below in reference to the components of the ram block carriers 160 and their movement within the cavities 124.

FIG. 4 is a diagram illustrating an example of a ram block carrier 160 which is capable of holding more than one ram block 182, 184, as discussed below. In one aspect, this provides a versatility in the types, sizes, and numbers of ram blocks used within a single blowout preventer, and allows an operator to efficiently switch between ram blocks without the burden of accessing the interior cavities of the blowout preventer and needing to retest the blowout preventer stack.

Referring to FIG. 4, the ram block carrier 160 includes detent button holders 166 and detent buttons 167, a extension tab 163 for use in the hydraulic actuation of the carrier 160, and a rack 162 for use in the mechanical override actuation of the carrier 160. Referring back to FIGS. 2 and 3, the blowout preventer 100 includes two ram block carriers 160, each placed within one of the two cavities 124 of the housing 110. The carriers 160 are moved up and down within the cavities 124 of the housing 110. When the ram block carriers 160 are in the lower position, the detent buttons 167 are engaged with the lower grooves 114 of the housing 110, whereas ram block carriers 160 in the upper position have detent buttons 167 engaged with the upper grooves of the housing 110. Accordingly, the detent buttons 167 slide along the interior walls of the cavities 124 as the carriers 160 are moved up and down. For example, the detent buttons 167 may include springs which support the buttons 167 within the button holders 166 and allow the buttons 167 to be pushed inwardly for disengaging from the grooves 114, 115 upon up and down movement of the carriers 160.

In an example, the ram block carrier 160 includes an upper shelf 165 and a lower shelf 164 for receiving an upper ram block 182 and a lower ram block 184. The carrier 160, including the ram blocks 182, 184 installed therein, can be seen in FIG. 5A. The ram block carriers 160 are configured to carry one or more ram blocks 182, 184. In this example, the ram block carriers 160 carry two ram blocks 182, 184 each, the upper ram block 182 and the lower ram block 184, but it should be appreciated that the number of ram blocks carried by the ram block carrier 160 is not limited thereto. For example, the ram block carriers 160 may carry three or more ram blocks.

Further, the ram block carriers 160 may be smaller in height, width, and length than the cavities 124 of the housing 110. This allows the ram block carriers 160 to move up and down within the housing 110. It should be appreciated that the ram block carriers 160 may be formed according to a variety of different sizes based on the types and sizes of the ram blocks 182, 184 used within the ram block carriers 160. In an example, the carriers 160 may accommodate 3 inch thick or 5 inch thick ram blocks on the upper and lower shelves 164, 165. The height of the ram block cavities 124 of the housing 110 may be at least two times the height of the openings formed within the interior wall of the housing 110. The upper and lower ram blocks 182, 184 may have the same size or may have different sizes. Also, the upper and lower ram blocks 182, 184 may be of the same type or may be of different types. For example, the upper ram blocks 182 and the lower ram blocks 184, or three or more ram blocks installed within the blowout preventer 100, may include any one or more of pipe, blind, shear, and blind shear ram blocks.

For purposes of understanding the movements within the blowout preventer 100, the actuation of the ram blocks 183, 184 into an open, retracted position and closed, engaged position, and the actuation of the ram block carriers 160 into an upper and lower position will be described below. Regarding the movement of the ram blocks 183, 184, the blocks 183, 184 are moved between a retracted position and an engaged position about the pipe of the bore 120 using a hydraulic actuator 170 or a mechanical override stem 190 which will be described below with reference to FIGS. 5A-5B. Regarding the movement of the ram block carriers 160, the carriers 160 move up and down within the cavities 124 of the housing 110 using a separate hydraulic actuating mechanism 150 or mechanical override mechanism 155, 162 which will be described below with reference to FIGS. 6A-6D. Different positions of the ram blocks 183, 184 and ram block carriers 160 will be discussed with reference to FIGS. 7A-7B and 8A-8B.

FIGS. 5A and 5B are diagrams illustrating front and top cross-sectional view of an example of the blowout preventer 160 including hydraulic actuators 170 and mechanical override stems 190.

Referring to the example illustrated in FIGS. 5A and 5B, each hydraulic actuator 170 includes a hydraulic cavity 171, an interior actuating rod 173, an exterior actuating rod 172, a piston 174, fasteners 175 for securing the actuating rods 172, 173 to the piston 174, and ram open/close hydraulic fluid ports 176, 177. As shown in the figures, when the ram blocks 182, 184 are in the retracted position, the piston 174 is furthest away from the housing 110. To move the ram blocks 182, 184 to the engaged position, hydraulic fluid is injected into the hydraulic cavity 171 through the ram-closed fluid port 177 and the piston 174 is pushed towards the housing 110. This in turn pushes the interior actuating rod 173 into the ram block 182 and closes the ram block 182 in on the pipe of the bore 120. Similarly, to move the ram blocks 182, 184 back to the retracted position, hydraulic fluid is injected into the cavity 171 through the ram-open fluid port 176 and the piston 174 is pushed away from the housing 110.

In the event of failure of the hydraulic actuator 170 or as an alternative to hydraulic actuation, blowout preventer 100 includes override mechanical actuator stem 190 for mechanical actuation of the ram blocks 182, 184. Mechanical actuator stem 190 is placed on the end of a stem protector 192 using roller bearings 194 which allow the stem 190 to be twisted for initiating mechanical actuation. When the stem 190 is twisted manually by an operator or using a machine, rotation of the stem 190 causes a threaded push rod 196 within the stem to pull away from the stem 190 and to be pushed inwardly towards the housing 110. This in turn pushes the entire actuating system, including the exterior actuating rod 172, the piston 174, and the interior actuating rod 173, into the ram block 182 for actuating into an engagement position. It should be appreciated that the length of the actuator stem 190 and push rod 196 is at least sufficient to extend the ram block 182 into an entirely engaged position, however, a number of lengths and sizes may be adopted and are appreciated to a person having ordinary skill in the art.

The stem protector 192 may include windows 193 which allow an operator to monitor the hydraulic and mechanical actuation of the ram blocks 182, 184. For example, the push rod 196 includes an end holder 197 which receives the exterior actuating rod 172. The end holder 197 includes one or more holes showing the position of the exterior actuating rod 172 with respect to the end holder 197. When the hydraulic actuator 170 is in the retracted position, an operator is able to see that the exterior actuating rod 172 is fully inserted within the end holder 197. When the hydraulic actuator 170 is in the engaged position, an operator is able to see that the exterior actuating rod 172 has separated from the end holder 197. Similarly, by monitoring the position of the end holder 197 with respect to the windows 192 of the stem protector 193, an operator may determine whether the mechanical actuator stem 190 has been engaged and whether the push rod 196 is fully inserted within the mechanical actuator stem 190. Indicators or markings may be added to any one or more of these components to allow the operator to determine the degree of hydraulic or mechanical actuation. Additionally, sensors may be used to detect the relative positions of these components for notifying an operator.

FIG. 5C is a diagram illustrating an example of a ram block 182 including a T-slot 183 connection to an actuating rod 173.

Ram blocks 182, 184 are engaged one at a time with the interior actuating rod 173 through a T-block connector 180 which is attached at the end of the interior actuating rod 173. The T-block connector 180 is configured to be received by each of the ram blocks 182, 184 through a T-slot 183. When the ram block carrier 160 is in the lower position, the T-block connector 180 is engaged with the T-slot 183 of the upper ram block 182, and when the ram block carrier 160 is in the upper position, the T-block connector 180 is engaged with the T-slot 183 of the lower ram block 184. Accordingly, due to the shape and size of the T-slot 183, the up and down movement of the ram block carrier 160 simply allows the T-block connector 180 to slide between the T-slots 183 of the different ram blocks 182, 184. It should be appreciated that the size of the components of the ram block carrier 160 and carrier actuating mechanisms 150, 155, 162 allow the T-block connector 180 to move to an engagement position with each T-slot 183 of the ram blocks 182, 184. Additionally, a programmable actuator may be utilized to position the T-block connector 180 within the T-slots 183 of each ram block 182, 184.

FIGS. 6A and 6B are diagrams illustrating side cross-sectional views of an example of a blowout preventer including a hydraulic actuator 150 for movement of the ram block carrier 160 into an upper position and a lower position.

Ram block carrier 160 is configured to be in a lower position, as shown in FIG. 6A, when the upper ram block 182 is active and the lower ram block 184 is idle. Also, ram block carrier 160 is configured to be in an upper position, as shown in FIG. 6B, when the lower ram block 184 is active and the upper ram block 182 is idle. Referring to the examples illustrated in FIGS. 6A and 6B, the movement of the ram block carrier 160 into the upper and lower positions may be controlled by a hydraulic actuator 150. The hydraulic actuator 150 includes an actuating piston 151, an actuating stem 152, an extend port 153, and a retract port 154. The upper end of the actuating stem 152 may be attached to the ram block carrier 160 using an extension tab 163 of the ram block carrier 160 for receiving the actuating stem 152.

In an example, hydraulic fluid controlled by an operator is injected into the extend port 153 and into a cavity of the hydraulic actuator 150. This causes the actuating piston 151 to rise which in turn pushes the actuating stem 152 and the attached ram block carrier 160 into the upward position shown in FIG. 6B. A retract port 154 may be controlled by an operator to withdraw hydraulic fluid from the cavity of the hydraulic actuator 150. This causes the actuating piston 151 to drop and in turn pulls the actuating stem 152 and the attached ram block carrier 160 into the downward position shown in FIG. 6A.

Hydraulic fluid which operates the hydraulic actuator 150 of the ram block carrier 160, and hydraulic fluid which operates the hydraulic actuator 170 of the ram blocks 182, 184 may be stored in a hydraulic panel which is formed within or outside the blowout preventer 100. Additionally, control of the hydraulic actuators 150, 170 may be operated manually by an operator, or may be operated according to a programmable control unit and in response to sensors which detect conditions of the carrier 160 and ram blocks 182, 184. For example, a sensor may detect that a ram block 182 is in a worn condition and programmable control unit may operate hydraulic actuator 150 to move the ram block carrier 160 into the upward position.

FIGS. 6C and 6D are diagrams illustrating an example of a blowout preventer 100 including a mechanical override mechanism 155, 162 for movement of the ram block carrier 160 into an upper position and a lower position.

Ram block carrier 160 is configured to be in a lower position, as shown in FIG. 6C, when the upper ram block 182 is active and the lower ram block 184 is idle. Also, ram block carrier 160 is configured to be in an upper position, as shown in FIG. 6D, when the lower ram block 184 is active and the upper ram block 182 is idle. As shown more clearly in FIG. 6D, when the ram block carrier 160 is in the upper position, the detent button 167 of the ram block carrier 160 is in the upper groove 115 of the housing 110 and when the ram block carrier 160 is in the lower position, the detent button 167 is in the lower groove 114. Accordingly, as the carrier 160 is actuated into an upward or downward position, detent button 167 is depressed inwardly against a supporting spring and slides against the wall until it reaches the corresponding groove 114, 115. The detent button 167 is then pushed out by its supporting spring once it reaches the corresponding groove 114, 115. The detent button 167 may have the same size or a smaller size than the openings of the groove 114, 115 such that it fits fully within the groove 114, 115 in its rest position. In this example, the detent button 167 is larger such that it protrudes from the groove 114, 115 in its rest position within the groove 114, 115. In this example, two grooves 114, 115 and two detent buttons 167 are shown, but it should be appreciated that the number of grooves may vary according to the number of ram block 182, 184 used or may be different than the number of ram blocks 182, 184. Also, one or more detent buttons 167 may be used on each ram block carrier 160.

Referring to the examples illustrated in FIGS. 6C and 6D, the movement of the ram block carrier 160 into the upper and lower positions may be controlled by a mechanical override mechanism 155, 162 in the event that hydraulic actuation fails or as an alternative to hydraulic actuation. The mechanical mechanism includes a pinion 155, a rotating pin 156, and a pin retractor 157. The pinion 155 may be engaged with the rack 162 of the ram block carrier 160 so that the ram block carrier 160 moves up and down based on the rotation of the pinion 155.

The rotation of the pinion 155 is controlled by the twisting or rotation of the pin 156. Rotating the pin 156 in one direction causes it to move in one direction against the rack 162 and causes the carrier 160 to move up. Rotating the pin 156 in another direction causes it to move in another direction against the rack 162 and causes the carrier 160 to move down. Accordingly, indicators may be added on the outside of the pin 156 or the pin retractor 157 which allow an operator to monitor the rotational position of the pin 156 to determine the position of the pinion 155 with respect to the rack 162 and the overall position of the ram block carrier 160. Additionally, sensors may detect the rotation of the pin 156 for notifying an operator.

In an example, pin 156 may be rotated manually by an operator using a wrench or automatically. Pin 156 may be rotated using a number of different machines or tools which are known to a person having ordinary skill in the art. For example, pin 156 may be rotated using a variety of electrical motors, hydraulic motors or other rotating devices. When the blowout preventer 100 is used in deep water situations, the mechanical actuator 156 of the ram block carrier 160 or the mechanical actuator 190 of the ram blocks 182, 184 may be operated using a remotely operated vehicle (ROV). The ROV could be used to supply hydraulic fluid to operate a motor or could be used to directly rotate the mechanical actuators 156, 190.

FIGS. 7A and 7B are diagrams illustrating a side cross-sectional view of the blowout preventer 100 with the ram block carriers 160 being in the lower position. When the ram block carriers 160 are in the lower position, the upper ram blocks 182 may be engaged and closed around the pipe within the bore 120, while the lower ram blocks 184 are in an idle position. In FIG. 7A, the hydraulic actuator 170 is connected to upper ram block 182 by the T-block connector 180, and the upper ram block 182 is in the retracted position. In FIG. 7B, the hydraulic actuator 170 is operated to push the upper ram block 182 into the engaged position about the bore 120. As previously described, an operator of the blowout preventer 100 is able to determine that the hydraulic actuator 170 is in the ram-closed position by detecting that the exterior actuating rod 172 is separated from the end holder 197. One or more sensor may be used in any of the components, such as the exterior actuating rods 172, the end holder 197, the stem protector 192, the pinion 155, the rack 162, and the hydraulic actuators 150 to sense relative positions of the components and notify an operator of a status of the hydraulic actuators 170, 150 or mechanical actuators 190, 162, 155 of the ram blocks 182, 184 and ram block carriers 160.

FIGS. 8A and 8B are diagrams illustrating a side cross-sectional view of the blowout preventer 100 with the ram block carriers 160 being in the upper position. When the ram block carriers 160 are in the upper position, the lower ram blocks 184 may be engaged and closed around the pipe within the bore 120, while the upper ram blocks 182 are in an idle position. In FIG. 8A, the hydraulic actuator 170 is connected to the lower ram block 184 by the T-block connector 180, and the lower ram block 184 is in the retracted position. In FIG. 8B, the hydraulic actuator 170 is operated to push the lower ram block 184 into the engaged position about the bore 120. As discussed previously, an operator of the blowout preventer 100 may be able to determine that the hydraulic actuator 170 is in the ram-closed position by seeing that the exterior actuating rod 172 is separated from the end holder 197 or by a signal from one or more sensors.

FIGS. 9 and 10 are diagrams illustrating a perspective view of another example of a blowout preventer 200. All features previously described in reference to blowout preventer 100 and accompanying figures may be used for blowout preventer 200. Accordingly, the descriptions provided above for blowout preventer 100, though not limiting in scope, are fully applicable for understanding the blowout preventer 200. In this example, the blowout preventer 200 includes circular rear door 230 and circular ram doors 240. Also, the mechanical actuator 255, 262 of the ram block carrier 260 is on the same side as the hydraulic actuator 250 for the ram block carrier 260.

Referring to FIGS. 11 and 12, the blowout preventer 200 includes a hydraulic actuator 250 for moving the ram block carrier 260. Also, a mechanical actuating system includes a rack 262 installed on the ram block carrier 260, a pinion 255, a rotating pin 256, and a pin retractor 257. The hydraulic actuator 250 and the mechanical actuating system 255, 262 may operate like the hydraulic actuator 150 and the mechanical actuating system 155, 162 of the blowout preventer 100. In this example, the hydraulic actuator 250 and the mechanical actuating system 255, 262 are installed on the same side of the blowout preventer 200 as shown in FIG. 11.

Still referring to FIGS. 11 and 12, the blowout preventer 200 includes a circular rear door 230 and circular ram doors 240. In this example, the circular rear door 230 and circular ram doors 240 include the same components and operate in the same way; however, a variety of different doors may be used with the blowout preventer 200. Circular ram doors 230 include a covering member 241, a top plate 242, a bottom plate 243, four through holes 244 going through the top plate 242, and four fasteners 245 extending through the through holes 244 and into the bottom plate 243. The bottom plate 243 has an opening in the center, thus allowing a user to inspect or access the interior of the blowout preventer 200. In this example, the circular ram doors 240 may be opened by removing the four fasteners 245 and subsequently removing the top plate 242 from the bottom plate 243.

Additionally, the covering member 241 includes a threaded hole 247 for receiving a threaded screw 248 extending from the bottom plate 243 through the top plate 242 and into the threaded hole 247. In this example, a flange 246 is placed between the covering member 241 and the top plate 242. For example, a user may rotate the covering member 241 thereby unscrewing the threaded hole 247 from the threaded screw 248, and allowing an opening within the top plate 242 to be exposed. This allows inspecting of the interior of the blowout preventer 200 and releasing pressure build up within the blowout preventer 200.

One of skill in the art will recognize that the described examples are not limited to any particular size. Further one of skill in the art will recognize that the blowout preventer 100, 200 is not limited to any type of material. As a non-limiting example, the blowout preventer 100, 200 is formed primarily from low alloy steel. In another example, metal components utilized in manufacture, when possible and not restricted by pressure constraints or other operational reasons, may be manufactured and machined from commercially available 4130 steel. One skilled in the art will recognize that other diameters, types and thicknesses of steel or preferred materials can be utilized when taking into consideration safety and the high pressure functioning capacity which can range in operation from 3,000 psi to 20,000 psi. In an example, a housing of the blowout preventer 100, 200 may be machined and ram block carriers may be cast; however, a number of manufacturing techniques may be used such as the machining or casting of any component of the blowout preventer 100, 200.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that the invention disclosed herein is not limited to the particular embodiments disclosed, and is intended to cover modifications within the spirit and scope of the present invention. 

1. A ram block carrier, comprising: an opening; an upper shelf within the opening configured to hold an upper ram block; and a lower shelf within the opening configured to hold a lower ram block.
 2. The ram block carrier of claim 1, further comprising an extension tab configured to be attached to a carrier hydraulic actuator for moving the ram block carrier.
 3. The ram block carrier of claim 1, further comprising a rack configured to contact a pinion for moving the ram block carrier.
 4. The ram block carrier of claim 1, further comprising a detent button configured to be pressed in response to the ram block carrier moving, inserted into an upper groove in response to the ram block carrier being in an upper position, and inserted into a lower groove in response to the ram block carrier being in a lower position.
 5. A housing of a blowout preventer, comprising: a bore; a first cavity on a side of the bore; a second cavity on another side of the bore; and inside walls, adjacent to the first and second cavities, each comprising an opening which allows a ram block to access the bore, wherein the first cavity and the second cavity are each configured to receive a ram block carrier that is movable within the housing.
 6. The housing of claim 5, further comprising outside walls, adjacent to the first and second cavities, each comprising: a pinion which is configured to contact the ram block carrier and to move the ram block carrier within each cavity; and an indicator which is configured to indicate a position of the ram block carrier.
 7. The housing of claim 5, wherein a length of each of the cavities is at least two times greater than a length of each of the openings.
 8. The housing of claim 5, further comprising outside walls, adjacent to the first and second cavities, each comprising: an upper detent groove; and a lower detent groove, wherein the upper detent groove is configured to receive a detent button of the ram block carrier in response to the ram block carrier being in an upper position and the lower detent groove is configured to receive the detent button of the ram block carrier in response to the ram block carrier being in a lower position.
 9. The housing of claim 5, further comprising outside walls, adjacent to the first and second cavities, each comprising a hole configured to receive a ram block hydraulic actuator for moving one or more ram blocks towards the bore.
 10. A blowout preventer, comprising: a housing; a ram block carrier configured to move within the housing; and one or more ram blocks configured to be placed within the ram block carrier.
 11. The blowout preventer of claim 10, further comprising a carrier hydraulic actuator for moving the ram block carrier within the housing.
 12. The blowout preventer of claim 10, further comprising: a piston; and an actuating stem attached to the piston, wherein the ram block carrier comprises an extension tab which is attached to the actuating stem for moving the ram block carrier.
 13. The blowout preventer of claim 10, further comprising a carrier mechanical actuator for moving the ram block carrier within the housing.
 14. The blowout preventer of claim 10, further comprising: a pinion installed on the housing; a rotating pin for rotating the pinion; and a rack installed on the ram block carrier and contacting the pinion, wherein the ram block carrier moves within the housing in response to the pinion rotating.
 15. The blowout preventer of claim 10, further comprising an indicator for monitoring a position of the ram block carrier.
 16. The blowout preventer of claim 10, wherein the one or more ram blocks comprises a plurality of ram blocks.
 17. The blowout preventer of claim 10, further comprising: a central bore extending through the housing; another ram block carrier configured to move within the housing; and one or more ram blocks configured to be placed within the other ram block carrier, wherein the ram block carrier is on one side of the central bore and the other ram block carrier is on another side of the central bore.
 18. The blowout preventer of claim 17, wherein the one or more ram blocks of the ram block carrier comprises a plurality of ram blocks, and the one or more ram blocks of the other ram block carrier comprises another plurality of ram blocks.
 19. The blowout preventer of claim 18, wherein each of the plurality of ram blocks of the ram block carrier corresponds to one of the other plurality of ram blocks of the other ram block carrier.
 20. The blowout preventer of claim 10, further comprising a ram block hydraulic actuator configured to move the one or more ram blocks.
 21. The blowout preventer of claim 10, further comprising: a piston; an exterior actuating rod attached to the piston; an interior actuating rod attached to the piston; and a connector on an end of the interior actuating rod for making contact with and moving the one or more ram blocks.
 22. The blowout preventer of claim 10, further comprising a ram block mechanical actuator configured to move the one or more ram blocks.
 23. The blowout preventer of claim 21, further comprising: a mechanical actuator stem; and a push rod threadedly engaged to the mechanical actuator stem, wherein in response to rotating the mechanical actuator stem, the push rod pushes the exterior actuating rod into the piston and the interior actuating rod, and the one or more ram blocks are moved.
 24. The blowout preventer of claim 10, further comprising one or more doors attached to the housing by fasteners.
 25. The blowout preventer of claim 10, wherein the one or more doors are circular doors configured to be opened by removing the fasteners.
 26. The blowout preventer of claim 25, wherein the one or more circular doors comprise a covering member, a top plate, and a bottom plate, and pressure within the blowout preventer is released in response to an opening of the covering member.
 27. A method of operating a blowout preventer, the method comprising: moving a ram block carrier within the blowout preventer; and moving a ram block of the ram block carrier towards a bore of the blowout preventer.
 28. The method of claim 27, wherein the moving of the ram block carrier comprises injecting hydraulic fluid into a carrier hydraulic actuator, and the moving of the ram block comprises injecting hydraulic fluid into a ram block hydraulic actuator.
 29. The method of claim 27, wherein the moving of the ram block carrier comprises rotating a pin on an outside of the blowout preventer and attached to a pinion on an inside the blowout preventer, and moving the ram block comprises rotating an actuator stem on an outside of the blowout preventer.
 30. The method of claim 27, wherein the moving of the ram block carrier comprises moving the ram block carrier into an upper position in order to use a lower ram block installed on a lower shelf of the ram block carrier.
 31. The method of claim 30, wherein the moving of the ram block carrier further comprises moving the ram block carrier into a lower position in order to use an upper ram block installed on an upper shelf of the ram block carrier.
 32. The method of claim 31, wherein the moving of the ram block carrier into the upper position causes a connector of a ram block actuator to engage with the lower ram block, and the moving of the ram block carrier into the lower position causes a connector of a ram block actuator to engage with the upper ram block. 